A. Field of the Invention
The invention relates to suction-type or vacuum cleaning apparatus and, more particularly, to such apparatus which applies a liquid cleaner to a carpet or furniture to be cleaned immediately prior or simultaneously with application of suction from a vacuum source.
B. Background of the Prior Art
Apparatus for the vacuum extraction of liquid and dirt from an item to be cleaned are known. In such apparatus, a spray of liquid is imparted through a nozzle to an object to be cleaned (typically furniture or a carpet) and, at the same time, a vacuum is applied through the nozzle to suck up the applied liquid together with removed dirt. Such apparatus are known to include a recovery chamber connected to a vacuum source for receiving the extracted liquid and dirt. Such chambers may include a device which shuts off the vacuum to the recovery chamber when the liquid level reaches a predetermined height.
In Canadian Pat. No. 1,135,910, a recovery chamber is shown with a float having a gasket at the top. As the liquid level rises, the float will rise to a point where the suction provided at an inlet end 52 will cause the float and gasket to close the inlet end. Since this arrangement relies on a substantial degree of suction to effectuate cut-off, in a situation where there is reduced suction for whatever reason, cut-off may not occur early enough. Further, if there is substantial foaming, the foam may enter the near horizontally arranged inlet 52.
Canadian Pat. No. 1,045,315 discloses two different cut-off arrangements in a recovery chamber wherein a float mechanism cuts off vacuum flow by closing a pair of holes which allow vacuum to enter a vacuum chamber. These arrangements were designed to avoid high foam build-up, however, these arrangements are structurally complicated and will require a greater than usual vacuum requirement. Further, since currently used cleaning solutions for such apparatus employ desudsing agents which prevent such build-up, this type of structure is not designed for current conditions.